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CORE JAVA 8 : The Complete Guide

2023-04-19T22:08:00.002-07:00

Introduction to Java

History and features of Java
Java Development Kit (JDK) and Integrated Development Environment (IDE) setup

Java Basics

Variables and data types
Operators and expressions
Control flow statements (if-else, loops)
Arrays

Object-Oriented Programming (OOP) Concepts

Classes and objects
Encapsulation, inheritance, and polymorphism
Abstraction and interfaces

Lambda Expressions and Functional Interfaces

Syntax and examples of lambda expressions
Built-in functional interfaces (Predicate, Consumer, Function)
Implementing your own functional interfaces

Streams and Filters

Stream API basics
Creating streams
Using intermediate and terminal operations
Parallel streams

Exception Handling

Types of exceptions
try-catch-finally blocks

Input and Output in Java

Streams and readers/writers
Serialization and deserialization

Date and Time API

Local and zoned date/time classes
Formatting and parsing dates and times

Default and Static Methods in Interfaces

Syntax and examples of default and static methods in interfaces

Multi-threading

Creating and managing threads
Synchronization and locks

Collections Framework

Collection interfaces and classes (List, Set, Map)
Iterators and comparators

Java Database Connectivity (JDBC)

Connecting to databases
CRUD (Create, Read, Update, Delete) operations

Java Web Development (Servlets and JSP)

Introduction to web development
Servlets and JSP basics

Containerize Your Spring Boot Application

2023-04-06T19:29:00.004-07:00

docker inspect postgres_db

172.18.0.2

rm -rf CAPEcommerceApplication

mvn install -DskipTests

To remove all Docker images at once, you can use the following command:docker rmi $(docker images -q)

=========================

sudo su -

yum install -y docker

systemctl start docker

systemctl enable docker

curl -SL https://github.com/docker/compose/releases/download/v2.5.0/docker-compose-linux-x86_64 -o /usr/local/bin/docker-compose

sudo chmod +x /usr/local/bin/docker-compose

sudo ln -s /usr/local/bin/docker-compose /usr/bin/docker-compose

sudo yum update

//sudo yum install maven

==================================================

To install Maven version 3.2.5 on Linux, you can follow these steps:

wget http://mirror.olnevhost.net/pub/apache/maven/maven-3/3.2.5/binaries/apache-maven-3.2.5-bin.tar.gz

tar xzf apache-maven-3.2.5-bin.tar.gz

sudo mv apache-maven-3.2.5 /opt/

export PATH=/opt/apache-maven-3.2.5/bin:$PATH

source ~/.bashrc

==================================================

mvn -version

sudo yum install git

git clone https://github.com/Haneesh55/CAPEcommerceApplication.git

cd CAPEcommerceApplication

mvn clean

mvn install

=================================

vi Dockerfile :

-----------------

FROM openjdk:17

EXPOSE 9090

ADD target/EMS-0.0.1-SNAPSHOT.jar app.jar

ENTRYPOINT ["java", "-jar", "app.jar"]

===================================

=============================

vi docker-compose.yml :

---------------------

version: "3.8"

services:

postgres:

image: postgres:latest

container_name: postgres_db

restart: always

environment:

POSTGRES_USER: postgres

POSTGRES_PASSWORD: root

POSTGRES_DB: TEST2

volumes:

- postgres-data:/var/lib/postgresql/data

app:

build: .

container_name: myapplication

depends_on:

- postgres

environment:

SPRING_DATASOURCE_URL: jdbc:postgresql://postgres:5432/TEST2

SPRING_DATASOURCE_USERNAME: postgres

SPRING_DATASOURCE_PASSWORD: root

ports:

- "9090:9090"

volumes:

postgres-data:

===============================================

docker-compose up -d

docker ps

===================================================================

O/P:CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES

d28628a514c9 capecommerceapplication_app "java -jar /app.jar" 21 seconds ago Up 19 seconds 0.0.0.0:8084->8084/tcp, :::8084->8084/tcp myapplication

e051a561ed84 postgres:latest "docker-entrypoint.s…" 21 seconds ago Up 20 seconds 5432/tcp

===================================================================

docker images

===============================================================

O/P:

REPOSITORY TAG IMAGE ID CREATED SIZE

capecommerceapplication_app latest 5bb91513b40e About a minute ago 522MB

postgres latest 680aba37fd0f 2 weeks ago 379MB

openjdk 17 5e28ba2b4cdb 10 months ago 471MB

=======================================================================

docker logs myapplication

<===== SPRING BOOT APPLICATION STARTED =====>

Tomcat started on port(s): 8080 (http) with context path ''

2023-02-25 16:44:21.749 INFO 1 --- [main]

com.cg.ecom.ECOMAppApplication: Started ECOMAppApplication in 17.076 seconds

<====================== THATS IT ==================>

============================================

Docker commands:

Running containers : docker ps

All containers : docker ps -a

Pull the image : docker pull [image-name]:[tag/version]

Shows the images : docker images

inspect the image : docker inspect [image-id]

create the container out of image : docker create [image-id]

start the container created : docker start [container-id]

instead of pull the image, create the container and start the container you can directly : docker run [image-name]:[tag/version]

docker run = pull + create + start

Options:

-d = detach mode

-P = assigns a random host port to container port

-p = you can choose the host port

hostport:container-port

docker run -d -p 8080:80 nginx

curl http://[IP-Address]:[host-port]

Enter the terminal of running container : docker exec -it [container-id] bash

Just execute the command no need to enter inside container. : docker exec [container-id] command

remove the container : docker rm [container-id]

-f = force

remove all containers : docker rm -f `docker ps -a -q`

environment variables

docker run -d -e key=value [container-id]

to check docker exec [container-id] env

docker volumes

by default docker removes the data when you remove the container, but you can create any folder in the host machine and map it to docker container using -v.

Now even you remove the container, data will not be removed you can attach it to another container again.

mkdir mysql-data

docker run -d -v ~/mysql-data:/var/lib/mysql mysql

Stopping Containers

docker stop <container-id> - Stop a running container with the specified ID.

docker stop $(docker ps -aq) - Stop all running containers on the host.

Removing Containers

docker rm <container-id> - Remove a stopped container with the specified ID.

docker rm $(docker ps -aq) - Remove all stopped containers on the host.

Force Removing Containers

docker rm -f <container-id> - Forcefully remove a container with the specified ID, even if it's still running.

docker rm -f $(docker ps -aq) - Forcefully remove all containers on the host, including running containers.

Removing Images

docker rmi <image-id> - Remove the image with the specified ID.

docker rmi <image-name> - Remove the image with the specified name and tag.

docker rmi $(docker images -aq) - Remove all images on the host.

Force Removing Images

docker rmi -f <image-id> - Forcefully remove the image with the specified ID, even if it's being used by a running container.

docker rmi -f <image-name> - Forcefully remove the image with the specified name and tag, even if it's being used by a running container.

docker rmi -f $(docker images -aq) - Forcefully remove all images on the host, even if they're being used by running containers.

docker run <image> - Start a new container based on the specified image.

docker run -d <image> - Start a new container in the background (detached mode).

docker run -it <image> - Start a new container in interactive mode (with a shell).

You can also specify additional options when starting a container. Here are some examples:

docker run -p <host-port>:<container-port> <image> - Map a host port to a container port.

docker run -v <host-path>:<container-path> <image> - Mount a host directory as a volume in the container.

docker run --name <name> <image> - Specify a name for the container.

The True Software Dev+Love+per

2022-10-02T08:04:00.010-07:00

<--------------------BY HANEESH----------------->

1) JAVA -: Introduction to Java,why java,Fundamentals of java,Oops,strings(StringBuilter and StringBuffer)

Exception Handling, Collections FrameWork,StreamAPI(lambda)

========================================================================

2) Spring Boot -:

Springboot Dummy Application, DTO'S, validations ,authentication.

Spring MVC , Spring Data JPA , H2 DataBase , Lombok

Concepts : jpa hibernate , spring vs springboot(versions) ,

Version Management(Dependencies,JRE/JVM,JDK), maven vs gradle

Dependency Injection (IOC , spring beans) , spring & springboot annotations

what happens when spring starts(Application context,Spring Container)

RESTFUL API'S, MicroServices vs Monolythic,test API Using Swagger

DevOps/ CI CD concepts (GitHub, CI-CD Jenkins, SonarQube,Sonar) + Strategy Design Patterns

TDD with Junit 5,Mockito.

========================================================================

3) Docker : Architecture ,containerization

Kubernetes : Kubernetes cluster Architecture ,Container Deployment (EKS)

========================================================================

4) AWS :

AWS Tools & Services

========================================================================

Top 5 DevOpsTools(OS:LINUX)

1) Docker

2) kubernetes(Container Archestration)

3) CI-CD : Azure Devops or github actions

4) IAAS : TERRAFORM

5) Cloud : AWS/AZURE/GCP

=========================================================================

THE BEST

2021-08-09T01:17:00.004-07:00

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2021-04-05T20:09:00.012-07:00

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2020-09-11T22:20:00.002-07:00

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2020-09-06T08:29:00.002-07:00

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Best Inverters

2020-09-05T21:37:00.009-07:00

Measure should be taken After purchasing the inverter :

1) Don't Keep Battery or inverter directly on the Earth or on Any Floor in your house . This will dame the Battery/ Inverter life . Use Any Base material like Cardboard or thermocol .

2) Refill the Tubes of the Battery for every 6months with distilled water

3) Maintanence is Mandatory

4) After Fixing the invertor Ask you agent to Re-check whether the Battery Terminals are Tight. Otherwise Due to Hysteresis Loss Sparks Will be Generated & this Lead to damage the terminals .

5) After 1 or 2 year's Apply Grease to Terminals of the Battery , Otherwise this will lead to Rust .